The present invention relates to a CATV system, and to a data transmission process in a CATV system for transmitting data from terminal equipment to a head end system at a rapid rate.
Many CATV systems are characterized by two-way data communication through cables between the head end system and terminal equipment so that the head end can obtain data from a number of terminal devices and provide for communication with the remote terminals. The two-way communication is normally carried out by polling or interrogation to identify a terminal device. With an increased number of terminal devices, however, each terminal device should still be polled and data should be received in response to such polling. This requires a long total period to poll all of the terminal devices individually, and results in a variety of difficulties. For example, security service requires that data identifying the occurrence of a fire, burglary, gas leakage or the like in a home equipped with a terminal device be transmitted without delay in order to minimize danger and damage. Accordingly, it is undesirable to be required to have a long polling period under these circumstances.